1. Field of the Invention
The present invention relates to a liquid-filled display or amusement device, and more particularly relates to a liquid-filled display or amusement device having a liquid-filled container with a diving object disposed therein which rises and falls in response to pressure changes within the container.
2. Description of the Related Art
There is something fascinating about watching objects moving about inside a liquid-filled container, and perhaps the most common example of a liquid-filled display device is the water globe. The water globe typically consists of a small, sealed, transparent, water-filled container, which is hemispherical, spherical, or the like, and which has small objects disposed therein representing snowflakes, stars, etc. Typically, the objects are heavier than water and settle to the bottom of the container. Because the water globe has no means for moving the objects, it is necessary to shake or tilt the water globe to cause the objects therein to move.
Another way to cause objects in a liquid-filled container to move is to drive the objects using jets of water, waves, bubbles, or circulation or stirring of the water. Various such methods have been adopted in a variety of water-filled games or amusement devices. See, e.g., U.S. Pat. No. 3,535,805, to Peiperl, No. 4,032,141, to Tanimura, No. 4,142,715, to Matsumoto, No. 4,817,311, to Ong S. T., No. 4,923,429, to Lewis, and No. 5,213,540, to Yang.
However, none of the foregoing methods are amenable to creating a liquid-filled display or amusement device having a diving object therein. A diving object can be controlled so as to rise and fall in the liquid. A number of attempts to create such an object have been made. The deep sea diving game of U.S. Pat. No. 1,991,626, to Rawdon, features a diving figure, with a head section having a ball which contains an air bladder and which has perforations. A tube connects the air bladder with a bellows, and when the bladder is deflated (through the tube), water enters the ball through the perforations, causing the figure to become heavier than water and to descend. In another approach, Soviet Patent No. 1421355 (Mikrdprovod) shows a transparent vessel filled with water, and a hollow ball floating in the water. When a flexible element connected to the vessel is pressed, the increase of pressure in the vessel causes the ball to sink.
However, these conventional diving object devices suffer from a number of problems or possible drawbacks. The device in the Rawdon patent requires that the diving object be connected to an air tube. Thus, the diving object cannot be freestanding or self-contained. In the Soviet patent, when the flexible element is pressed and the pressure in the vessel is increased, the increased pressure could compress the hollow ball and cause its exterior to be deformed unattractively. Furthermore, changes in ambient conditions may affect its operation, because of the so-called "shrink and expand" phenomenon. In the shrink and expand phenomenon, changes in ambient conditions (i.e., the conditions in the room in which a sealed, liquid-filled container is placed) may affect the internal pressure within the container. For example, if the ambient temperature (i.e., the temperature in the room in which the container is placed) were to increase, so also would the temperature of the liquid within the container. This in turn would cause the liquid to expand, thereby increasing the internal pressure within the container. In like fashion, a dropping temperature would cause the liquid to shrink, thereby decreasing the internal pressure within the container.
When the internal pressure changes as a result of the shrink and expand phenomenon, two possible problems may arise. First, the change in internal pressure may cause the hollow ball to rise or fall in the liquid, independently of operation of the flexible element. Secondly, the change in internal pressure may cause the flexible element to change its free length, which is the length which the flexible element attains when the system is in equilibrium. This change in free length might make it difficult to couple a driving member to the flexible element so as to compress and/or decompress the flexible element, if such were desired.
Accordingly, an improved display or amusement device is needed to address the above-noted problems and possible drawbacks of conventional devices.